This application discloses an invention which is related, generally and in various aspects, to an anti-roll off assembly and a system including the same for preventing a tire mounted on a one-piece wheel from rolling off the wheel.
Many solid one-piece wheels include a disc portion and a rim portion. The disc portion is connectable to the hub of the vehicle. The rim portion is connected to the disc portion and includes a first flange portion, a second flange portion, a first seat portion, a second seat portion and a drop center portion. The first flange portion is at an axially outboard side of the rim portion and the second flange portion is at an axially inboard side of the rim portion. The first seat portion is axially inward from the first flange portion and the second seat portion is axially inward from the second flange portion. The drop center portion is positioned between the first and second seat portions and generally includes a bottom portion, a first side portion and a second side portion. The bottom portion of the drop center portion of the rim portion of the wheel has a smaller radial diameter than the first and second seat portions. In other words, the radial distance the drop center portion is from an axis of rotation of the wheel is less than the radial distance the first and second seat portions are from the axis of rotation of the wheel.
The smaller radial diameter of the drop center portion allows for a tire to be more easily mounted to the rim portion of the wheel. For example, a bead portion of a tire may be forcedly distorted so as to pass over one of the flange portions. Once this bead portion of the tire is passed over the one of the flange portions, the bead portion of the tire can then be dropped into the drop center portion. Once this bead portion of the tire is positioned in the drop center portion, the opposite bead portion of the tire can then also be easily passed over the one of the flange portions. Thus, the entire circumference of both tire bead portions may be passed over the one of the flange portions, step-by-step working around the circumference of the tire, until both bead portions are mounted to the rim portion. Upon pressurizing the inside of the tire, by use of a tire valve, both bead portions of the tire will be respectively forced axially outward so as to seat snugly upon the first and second seat portions and pressed axially outward against the flange portions.
Although the above arrangement allows a tire to be more easily mounted to the rim portion of a wheel, it also can make it easier for a tire to roll off the rim portion of the wheel while the vehicle is moving (and the wheel connected to the vehicle is rotating), especially in low tire pressure situations, flat tire situations and high speed cornering situations.
One approach to minimize the chance of tire roll-off occurring is to position a device circumferentially around the base of the drop center portion so as to partially fill the drop center portion. An example of such a device is disclosed in U.S. Pat. No. 7,469,732, the content of which is hereby incorporated in its entirety. Although such prior art devices are generally effective for wheels and tires utilized by automobiles and light-duty trucks, there are multiple reasons why such devices are generally not suitable for more demanding applications like commercial truck or bus applications.
For example, one reason is that commercial truck or bus applications require an increased band tensioning force capability over that of the device disclosed in U.S. Pat. No. 7,469,732. For that device, the belt loop attachment at each end of the belt is clamped together and spot welded without a formed radius at the vertex of the transition as shown in FIG. 1. As a result, the tensioning force capability of the belt of the device is significantly less than what is required in a typical commercial truck or bus application. More specifically, the band tensioning force (FT) created by the connecting means which connect the belt loops to one another creates a resultant force (FR) on the upper portion of the belt loop. The spot welds are then subject to destructive peel load forces (FP) from the vertical component created by the resultant force (FR), effectively reducing the tensioning force capability of the belt to an amount which is significantly less than what is required in a typical commercial truck or bus application.
Also, the connecting means which connect the respective belt loops to one another for that device requires a belt tightening nut positioned within one of the belt loops as shown in FIG. 2. In order to have the tightening nut positioned within one of the belt loops, a hardware clearance HC is provided within the belt as shown in FIG. 3. In various aspects, the required hardware clearance can consume up to 75% of the width of the belt. With such a relatively large amount of the width consumed by the hardware clearance HC, the tensioning force capability of the belt is generally significantly less than what is required in a typical commercial truck or bus application.
Additionally, the connection between the respective filling elements and the belt can become compromised when the belt is subjected to higher tensioning forces such as those utilized in many commercial truck or bus applications. When the connections become compromised, the spacings between adjacent filling elements can become non-uniform, the filling elements can lose their position within the drop center portion of the rim, and the device can ultimately lose its intended functionality (preventing the tire from rolling off the wheel).
Furthermore, for certain aspects of the device disclosed in U.S. Pat. No. 7,469,732, the respective filling elements can be adjusted radially and/or axially to meet the radial height and/or axial width of the drop center portion of the rim. However, for a given filling element, the adjustable structure and arrangement required to do so does not necessarily completely fill and/or block off the volume of the drop center portion of the rim associated with the given filling element. By the filling elements not completely filling and/or blocking off the volume of the drop center portion of the rim associated with the filling elements, the filling elements can sometimes move axially or radially within the drop center portion. Whenever this movement occurs, the device may not (1) adequately ensure that the bead portion of the tire does not enter the drop center portion of the rim and allow the tire to roll off the wheel and (2) be able to support the heavy loads generally associated with commercial truck or bus applications.
Another example of why such a device is not suitable for more demanding applications like commercial truck or bus applications is that the two belt loops at the ends of the belt are formed over respective transverse bars as shown in FIG. 4. With this structure and arrangement, the belt loops can slide laterally off of the transverse bars if there is any transverse bar misalignment during the device tightening process. This is especially so in typical commercial truck or bus applications where greater tensioning forces are applied to the belt. Of course, if a belt loop slides laterally off its corresponding transverse bar, the intended functionality of the device may be defeated (preventing the tire from rolling off the wheel).
Yet another example of why such a device is not suitable for more demanding applications like commercial truck or bus applications is that the connecting means which connect the respective belt loops to one another is a single sided fastener (See FIG. 5). The single sided fastener includes a sheath which has a first end which terminates in one of the transverse bars, a T-shaped rod which is positioned within the sheath and has a first end which terminates in the other one of the transverse bars, and the belt tightening nut threadedly mounted on a second end of the T-shaped rod and against a second end of the sheath). As the belt tightening nut is rotated in a first direction, the transverse bars are pulled toward one another, thereby tightening the belt around the rim portion of the wheel. As the belt tightening nut is rotated in a second direction which is opposite the first direction, the transverse bars are pushed away from one another, thereby loosening the belt around the rim portion of the wheel. By only utilizing a single sided fastener, the time required to tension the belt of the device is relatively slow. The relatively long time required to tension the belt has a relatively high cost associated therewith, thereby effectively rending the device not economically feasible for many commercial truck or bus operations.